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BYU Radio Astronomy Research Group -- Open Source Array Feed Codes

Advisors: Karl Warnick, Brian Jeffs Research Assistants: Jacob Waldron, Jonathan Landon, David Jones

Array Feed Codes

Background/Conventions:

All physical dimensions are in meters. Mutual coupling: the current codes (8/07) do not take into account the effect
of mutual coupling on receiver noise. Also neglected is the perturbation to the radiated
loaded fields used in reflector_response2.m and Overlap_Matrix.m due to the presence
of other open circuit loaded elements.

Example code that produces array receiver output correlation matrices and steering
vectors, determines optimal beamformer weights, and computes performance metrics (spillover efficiency, aperture efficiency, and sensitivity). The performance metrics are given as a function of array offset distance
relative to the focal plane.

Physical optics reflector analysis code (2D numerical integration). Implements a closer approximation for a finite length dipole than reflector_response.m.

This function computes the pattern overlap matrix for an antenna array. Image theory is used to
include the effect of a ground plane, where the ground plane is assumed to be infinite. The function returns
pattern overlap integrals over a full hemisphere, as well as overlap integrals over an annular region
representing the spillover region of a reflector. The spillover overlap matrix can
be used to obtain the spillover noise correlation matrix for the array as a feed for a reflector.

Computes the total Eletric field for each of the array elementsas well as the B_matrix from Dr. Warnicks ECEn 665 notes.
Also returns the signal covariance matrix.

Fast physical optics reflector analysis code with one dimensional numerical integration. This code is accurate for a Hertzian dipole and near-boresight elevation angles, but for a linear antenna requires that the azimuthal dependence
of the element pattern be neglected. (Note: reflector_response.m has been changed so that the offset variable
is in meters rather than wavelengths.) The test code includes conversions from transmitted fields to received voltages and a comparison to reflector_response2.m and TICRA results.

This function computes the pattern overlap matrix for an antenna array. The element patterns are
assumed to be hemispherical, approximating the effect of a backing ground plane. The function returns
pattern overlap integrals over a full hemisphere, as well as overlap integrals over an annular region
representing the spillover region of a reflector. The spillover overlap matrix can
be used to obtain the spillover noise correlation matrix for the array as a feed for a reflector.

Runs different beamformers on the data from the 19-element array test, including LCMV and Max-SINR. (Note: Requires complex_baseband.m, correlate.m, load_baseband_data.m, load_packed_data.m, load_packed_header.m, make_lpf_taps.m, and my_psd.m.)

Loads packed data and complex basebands it. Mean removal is being done before complex basebanding and it is done on a block-by-block basis. (Note: Requires complex_baseband.m, load_packed_data.m, load_packed_header.m, and make_lpf_taps.m.)